#include <stdio.h>

//extern：外部的
extern int myadd(int num1, int num2);
extern int mydiv(int num1, int num2);
extern int myminus(int num1, int num2);
extern int mymulti(int num1, int num2);


int main()
{
    int sum = myadd(100, 200);
    printf("sum:%d\n", sum);

    int cha = myminus(100, 200);
    printf("cha:%d\n", cha);

    int res = mymulti(100, 200);
    printf("res:%d\n", res);

    res = mydiv(100, 200);
    printf("res:%d\n", res);


    return 0;
}